Desilting valve



April 28, 1953 c. BLANCHET DESILTING vALvE 4 Sheets-Sheet l Filed Feb. 11. 1949 April 28, 1953 C. BLANCHET DESILTING VALVE 4 Sheets-Sheet 2 Filed Feb. ll. 1949 April 28, 1953 c. BLANcHl-:T

DESILTING vALvE 4 Shee's-Sheet 3 Filed Feb. ll, 1949 April 28, 1953 c. BLANcHET 2636,609

DESILTING VALVE Filed Feb. 11. '1949. 4 sneets-sneet 4 INVEN TOR.

HTTRNEY Pafente pr. ;1953

UNITED STATES PATENT VOFFICE DESILTING VALVE Charles Blanchet, Grenoble, France, assignor to Etablissements Neyrpic, Grenoble, France, `a

corporation of France Application February 11, 1949,seria,1No. 75,847 In France February l16, 1948 16 Claims. 1

The present invention relates to apparatus `for evacuating secliment, earth, sand, gravel or otherfine particulate material which is carried along in Suspension in a fiow of water or another fluid and which tends to settle' out and accumulate as the flow velocitydecreases, as, for example, when water is discharged from water courses into ponds, reservoirs and other hydraulic installations. More particularly, this invention concerns the provision of apparatus for efiecting such evacuation which will be hereinafter referred to as a desilting valve."

The accumulation of suspended matter in hydraulic installations gradually reduces the efficiency of such installations and necessitates relatively frequent Cleaning Operations which may result in an interruption in the use or effectiveness of the hydraulic installation involved. This applies especially to fine sedimentary matter which is heavier than the liquid in which it is present, such as the water intakes of hydraulic installations, desilting works and coal washers, as well as installations in which the liquid has little or no flow such as decanting basins.

It is, therefore, an object of this invention to provide a device by means of which sedimentary vmatter and other suspended solids may be removed from flowing or substantially still liquids. I It is a further object of the invention to provide a desilting valve which serves to establish a Controlled withdrawal of portions of the liquid that are adjacent the bottom of the reservoir, settling basin or other confining channel or container and consequently more heavily charged with the solid material while leaving thezliquid in the upper layers thereof toward the surface substantially undisturbed.

It is a further object of the invention to provide a desilting valve of simple construction which is automatically responsive to changes in the level of the liquid to increase or decrease the rate of flow to and through the evacuating pipe of' those portions of the liquid that are mor heavily charged with the sediment. i

Other and further objects and advantages will be understood by those skilled in this art or will be apparent or pointed out hereinafter. v In the accompanying drawings wherein I have -i1lustrated certain embodiments of this invention:

Fig; 1 is a diagrammatic elevational View of one form of my new desilting valve showingthe vertically movable tubular valve member in Vertical section.

-;Fig. 2 is a view generally similar to Fig. 1 of 'a modified form of the invention as applied to a hopper-shaped sand removal device.

Fig. 3 isa view similar to that of Fig. 1, but wherein amodified form of the tubular valve member is employed.

Fig. 4 is also a view similar to that of Fie'. 1 but wherein the evacuating pipe is arranged as a siphon.

Fig. 5 is a View generally similar to Fig. 1 but illustrates a modification in which the tubular valvemember is provided with means for reducing or stopping ,the fiow of fiuid to the evacuating pipe.

Fig. 6 is a view generally similar to Fig. l but illustrating a modified `form of the invention in which the evacuating pipe is arranged as a siphon and the tubular member is associated with means for reducing or stopping the flow of liquid to the pipe which is independently supported.

Figs. 7 and '8 arediagrammatic elevations of Views witha part broken away in section illustrating further modified forms of the invention in which the vertically movable tubular member is provided with an outwardly fiaring funnelshaped portion at its upper end and in which the evacuating pipe, in the form of a siphon, is pro- 'vided with an enlarged lchamber enclosing the upper end of the vertically. movable tubular member.

The present invention ,is predicated upon the use of a tubularmember whichV is vertically movable' andwhichiis .partially or Wholly submerged within the liquid containing the matter to be evacuated. This tubular member is provided. with'a portion of enlarged diameter adjacent its upper. end andis operably associated with a fixed pipe which may be arranged either as-a gravity actuated evacuating pipezor as a siphon. Under normally encountered working conditions wherein there ;is ino 'restriction of the upward flow of the water containing the matter to be evacuated as the result of an excessive accumulation of'suchV matter therein, the difierence'of the exterior and'interior pressures acting on the-tubular member remains approximately constant-and the position of such member in the river or;other body' of water is determined and controlled by the v'quantity of sediment on the fioor or bottom of such body of Water. When the-amount of sediment becomes large, so as to tend to jam the valve and reduce the upward fiow, the tubular member automatically rises due to an increas'einthe pressure difference until the initialjor normalupward fiow is re-established, thus evacuating the' sediment under what may be considered as normal or standard conditions. The sediment is discharged by the evacuating pipe at any suitable or desired remote point, as in a, river, Canal or other appropriate place.

Referring now to Fig. 1 of the drawings, the desilting vaive is located. adjacent the floor or bed of the canal, river or other ccnfining channel for the body of water'containing the matter "t'o be evacuated. This valve includes the vertically movable tubular member 2, the movements of which may be controlled by the guide members 3 which may be of any suitable construction Lforming no part of the invention. As shown in Figi, the tu'oular valve member 2 is composed of -alower cylindrical portion and upper cylindrical portion 4 connected by the frusto-conical intermediate portion li, it being particulariy noted'that the' upper cylindrical portion ft is of great'e'r'diamet'er than the lower cylindrical portion 5. Th'e evacuating pipe I in this form'of the invention has one end extending upward axiallyjinto andterminating within the -tubular member The evacuating pipe 'i leads to a suitable point ofdischarge andmay, for example, extend beneath the-door i of the ca'na'l or 'other conning'ohannel. V

The respective diameters ofthevcylindricalportions li and 5 are so related lthat -the'weight of the tubular member 2 is V'no'rmally' balanced by the dierence between the interior and exteriorrwater Vpres'sures ac'ting upon'the frusto-conical connecting portion 5 when the level'of the water inside the tubular memberis above the Vsaid 'frustoconical connecting 'portion Thus, assurn'ing that the tubular member 22 is initi-ally :empty and resting upon the oor 'of the canal or otherchann'el, it will be immediatelviifteddue to'thehydr'aulic pressure exerted on itsexterior wall surfaces and which at that instant is not balanced by an opposing pressure on'th'e interior surfac'es. As soon as water has entered 'and has risen to a suitable height above the connectin'g'wall port'ion 6 a state of balance o'r equilibrium will "be established. This height will'be'deter'mined by the loss of head set up'through th'e'evacuating pipe 7. The amount of discharge through ev'acuating pipe 'i and the relative 'Vertical height of the cylindrical sleeve 2 in the body of water thei'efo're depend upon'a loss of h'ea'd which is'equal to the difference 'between 'the levels of 'the'lbody' of water 8 and the level of the body of water 9 'which is present in the tubular member 2'.

It Will be seen that the cylindric'al sleeve a'ct's in the manner of a fioat asfare'sult of its'con'- figuraton and the difference's in' pressure 'exteriorly and interioriy thereo'f.VW vlfmring'the time the sleeve is in a condition of 'equiiibriuin the wa'- ter from the lower portions of the body there'of passes upwardly into the 'tubular member 'and then out throug'h the evacuating-'pip'e 'l, carrying with it the sediment or other'unde'sirable suspended matter which tends to concentrateinthe lower layers of the body of water adjacent the lower end of the tubular 'member 2. After the sedirnent-laden water enter's' the fme'mbe'r 2 it passes first upwardly therein 'and then down through the evacuatin'g pipe T'a's 'a' result of the head produced by the vdifference in v'the*li-:"el of the water in the valve and'the'water 'at the downstream or remote end of the evacuating pipe where the sediznent is dscharged. vIt is to .be understood, however, that the evac'uation 'can' be oarriedout by other methodssuch as by pumping, in whichcase a pump is suitably inserted lin the evacuating pipe at any tconvenient or accessible point thre'o When the defsilting valve is fune'. tioning normally, the upward now of sediment- 4 laden water thereinto is equal to the discharge through evacuating; pipe 1. To insure such a condition the valve is positioned near the region of the body of water in which the sediment collects and may even penetrate somewhat thereinto. In this manner, the best conditions for effective operation uof the valve are reaiized. I

In the :modified form of the inventi'oh 'illustrated in Fig. 2 the desilting valve composed of the tubular member 2 and the evacuating pipe 1 are installed within the hopper-shaped Sand-removing device Hi, a portion of the evacuating pipe I being suitably supported by an inclined extension of 'the device ijii,"as shown. In this case the tubuiar member 2 'is 'counter-balanced .by means of a. weight l which is connected to the upper end of V'he 'menrb'er Zby lmeans of Cable i2 which intermedi'ately 'passes over the pulleys l and M. The 'principles of operation are the same as explained in connection with Fig. 1, but the arrangement of Fig. `2 has lthe additional advantage that the weight of the valve member 2 'isv'partly'bal- -anc'ed by means of the counter-weight -l lv, afnd hence the buoyanoy of the valve 1n`ember`is 'niaterially increased.

The form of desilting valveiilustratedin'Fie3 is essentially the same as that of Fig', 1 'eiioept that the tubuiar member `2 is provided with an annul'ar seat or step ii' between the upper and lower-cylindrical portions `Hand 4 and an 'annular hollow float element `!5 is disposed on and secured Ato such seat or'step in order 'to provide increa'sed buoyancy in a different and simpler "m'ahne'n Thus the 'tubular member of Fig. v'is'i'iot provided With a fru'sto-oonic'al c'onnectihg'portidn, but otherwise responds to the t'ubular'inember of Fig. 1, as Will be apparent.

It will be noted in connection'with the mod'i'fications of Figs. 1, 2 and 3 that the upper end 'of the tubular member 2 extends 'above the'l'evel of the body of water 8 and is open' to the atmosphere. The lower end of the tubular member inormally is r'elatively close to but some'what spac'ed from the fioor or bottom of the 'channel but is capable of upward and downward mov'ement in .response to changing conditions as already e'xpiained anent Fig. 1. The preci'se position of thetubular memher 2 with respect to the floor or bottom 'i andA the intake end of the evacua'ting pipefi depends upon conditions at any given time with espe'cial're'ference to the amount of sediment or other matter to be/discharged and the'loss of head'established through the evacuating pipe 1. These forms of the `invention are further characterized in that they insure the effective evacuation of the sediment-laden water whiie perihitting inaiirnumruti'- lization of the head whichis determined by the difference in the levels of the free water 'surface of the body of water 8 and thedischarge'point of the sediment. In those instances -in which the discha'rge or dumping point'o'f the-sedirnent i'nvolves a relatively high water fleveL-the arra-ngement of the evacuating pipe T'can b'e' varied to avoid low points andthereby `tol provide a greater assurance of sediment evacuation, aith'o'ugh this is not significant when a pump 'lis' provided in-the evacuating line.

Fig. 4 illustrates how the 'ben'efit's 'of the'prese'nt invention 'ca-n b'e i'ea'lized under'icohditio'ris such as referred to just above. While the tubular member 2 is the same as that of Fig. l, the e'v'a'cuating pipe it is arran'ge'd as a. 'sipho'nand therefor'eV has its intake end exten'ding dow'nwardly into the member -2 through' the 'upper end'o'f' such member in contrast to the evacuating pipe=-1flpre=- viously 'descri'bed which has its intake end :ex-

5. tnding 'upwardly intothe bottom of said member. In both. cases the intake .end of the evacuating pipe .is located somewhat below the point of enlargement of the tubular member 2. The desilting valve of Figfl has the particular advantage thatthe pipe JB cannot become blocked due to the fact that sediment in the valve tends to fall either .into the interior of the valve 2 or passes down the evacuating pipe to the point of disposal.

When the amount of sediment or other matter in the water becomes reduoed to a point where it is unobjectionable, I have found that it is desirable to be able to reduce the loss of water through the evacuating pipe and hence I have illustrated in Figs. 5 and 6 arrangements whereby the flow of water to the .evacuating pipe Can be reduced. In Fig. 5 the intake end of the evacuating pipe is located vjust Vbelow a special conical plug li which is suitably mounted within the tubular valve member 2 at the upper end of the frusto-conical connecting portion between the upper and lower cylindrical portions thereof. When, due to the decrease in the matter to be'evacuated, the valve 2 descends, the plug l'i efiectively coopcrates with the upper end of the evacuating pipe to diminish the outward flow of .water through such pipe. In Fig. 6 the same result is secured in connection with a siphon-type of evacuating pipe by providing the valve 2 with an inner tubular member le supported. centrally of the opening therethrough and so disposed lengthwise thereof as normally to surround the intaize end of the pipe lt so that when the valve descends the tube lt is entered and blocked by a cylindrical rod 10 having substantially the same diameter as the pipe E6 and which is suitably mounted or positioned on the floor or bottom I of the canal or other channel, as shown. As pointed out above, the Vertical movements of tubular valve member 2 are automatic and in response to the variations inthe pressure difference on the valve 2. Also, other things being equal the pressure dierence will vary with the amount of sediment or the like collecting on the floor or bed of the channel in the vioinity of the intake of the valve 2. When the amount of sediment decreases, the buoyant effect upon the valve 2 decreases and the valve therefore descends. This movement is taken advantage of in the embodiments of the invention shown in Figs. 5 and 6 for the purpose of diminishing the flow of water through the eva'cuating pipe during those times when the amount of sediment is lessened. It .will be appreciated also that the normal tendency of the cylindrical valve 2 is to descend and this tendency is offset either by the increase in the amount of sediment at the location of the valve or by the Drovision of means for increasing the buoyancy of thevalve as referred to above in connection with Figs. 1 and 2, for example.

I have further found that the upward movement of sediment into the interior of the valve can be facilitated by imparting a gyratory movement to the tubular valve member 2. This can be. accomplished by providing the interior survention. In these figures a modified form Vof the 6. vertically movable tubular member is employed which is designated by the numeral 20. This, like the member 2, is of generally cylindrical shape, but the upper end of the member 20 iS provided with an outwardly iiaring portion 2| giving to the member 20 the appearance offia funnel. The siphon-type evacuating pipe'l is provided with an enlarged chamber 22 at its intake end and the upper funnel-shaped section 2| of the member 20 is located withinsuch chamber 22. In Fig. 7 the enlarged Chamber 22 is entirely submerged, whereas in Fig. 8 it is only partially submerged and is supplementally .provided with a cylindrical extension 23. In each instance, however, the Chamber 22 has a Suitable opening 20 in order to allow for Vertical movements of the member 20. The enlarged chamber 22 of Fig. 7 is placed directly in the fiow of the water, but in Fig. 8 it is substantially above the water level in, order tol avoid eddies and-like disturbances in the flow of water.

4It isto be understood' that the foregoing represent examples of embodiments Abymeans of which the present invention may be carried into effect but that the same are intended as illustrative and not as limitative, since other and further variations and modifications may equally well be employed without departing from the principles of the invention. The invention embraces all. such embodiments of the invention as come within the terms or spirit of the appended claims 'and wherein a floating or nonfioating tubular vertically movable valve member is provided having the configurations and relative dispositions as above described. Furthermore, a desilting valve according -to this invention vmay be placed wherever desired or needed, singly or in any necessary number and spacing in'bodies of water such as Vrivers, oanals or decanting basins, or in troughs, hoppers or the like.V Finally, the sediment or othermatter to be discharged can be removed either` from the bottom of the cylindrical sleeve or section as by means of an evacuating pipe of the type designated by the numeral 'l of Fig. 1 or from the top of the'sleeve or section by a siphon-type of evacuating pipe such as shown at |6 in Figs. 4, 6, 7 and8`.

' I claim:

1. A desilting valve for hydraulic installations, comprising a tubular member open at both ends and adapted to be at least partially immersed in an upright position in a body of liquid containing sediment to be removed with the lower end of the member adjacent the bottom of said bOdy of liquid. an evacuating pipe having its inlet end in communication with the interior of said tubular member and spaced from the lower end thereof, said pipe being effective to-establish a discharge of liquid therethrough When the pressurel at its outlet end is lower than the pressure at its inlet end, said discharge being effective to lower the pressure within said member, said member having a substantially greater crosssectional area at the upper end of the immersed portion thereof than at its lower end, so that thepressure difference between the inside and outside 'of the member produces a buoyant force thereon, said buoyant force being effective When it exceeds the net weight of the member to lift said member, said lower pressure inside said member being effective When the member is so lift-ed to induce an upward flow from adjacent the bottom of the body of liquid into the member and thence through the evacuating pipe, said iiwardlfiow bengiefiectvetoientram seiiiment disposedfadiacent'saidibottom;

f12i-A:.desi1ting:=vaive .as .defi'ned vinLoiaimii, in which 'the'idifierexieelinSsaidofoss-seetional. area-'s isN so frelat'ed to "the net "Weight of: the tubular memberfthati ;the buoyantxforce! -on'` thefimember just balances fthefnetrweighti-.of the member whenfithe loiirerv fendsthereofis us'tzclear'vof -=the 'wheneby wansmcrease tnsamonntfof' siltadziaoentfthe.lowerrend:offsaidatubinar.ma ber'partially? clofs it, .fthereby' cmsirrg. the flow of. .*:finqiiid throughitthe'foudet .pipe-.to :"r'educe' the pressure finlthe i tubular member Land therehy" increase the .buoyantfforcethereon, vso ftliat'the :tubular mein-b' ei-Lrises and Fadmitsia=-greaterlnow of' liefui'dtto foaiw liih'e silt through: said :member and pipe, ;said flowrilimiting "valve 'ooml prising a valve'e'Iement-ffand:affcooperatingirseat element, `I`one of 'fsaid :'.elements' beingazstationary and the-'other rs'aid'element ieingimovable with' said tubular :nember'andficdoperat-ing withxsa'id stationary xelement to' redocer'the .flow 'through said eva'eoating:ipipe-asfwid member freacheszits lowermost ;position il. A desiiting'valvef-asf'efined ih'olaim 3;.`-in which' ``said =evacuating lfnipe -exte'nds up'wardly into-'said tubular 'memberfthrough the lower fend thereof; 'the upperend of '-'said foutletlp'ipe forms the-.seat element of saidfiow limiting valiand the=valve ifelement-isfoarried by! the tubular .memberv:5..A dosilting valve-as =defined'zin-claim 1, in which-said body `of-.liq'uidis en'closed in :al-contaner and in whichl said'ztubnlar member is fionly partly immersed, said .evacuatng `pipe is 'a siphon having its inlet Aend extendingl downwardly Within said tubu-lar `member, -and including a fiow limitin-g valve-at the inlet'of sai'd--siphon com'- prising ya -sleeve fsu-rround-ing` 'said--inlet yand Vcar-- riedby lsaid-v member, andza rod= fixed' on'the bottom of said voontaine:.and havingits upper end of -substantially the' same dimensions `IVas the sipho-n -inlet 'and aligned therewith land'spaced therefromgsaid sleevebeing adapted to 'close the space between the siphon nlet and said upper rod end as said member reaohes its lowermost position.

A zdesiltngvalve' as definedinolaim inoluding..means for ,guiding the Vertical "movementsof said tubularmemben 7. Adesilting valveas `defi1zu.=.'d.ir1- claimzvl, includinga 'ser-ies'of vanes rattached tothe inside of the.--lower2 end of .saidtubular member, so that thev action. of 'thefwater on.:said -vanes tendsto rotate the member.

8; A desilting Vvalve as definedin elaim .1, in whichsa-id evacuating 'pipe `'is 'a -drain pipe' extending through' the lower end of said' tubular member.

9'. Apparatus for removing sediment from a body'of liquid, Lcomprsing a tuloular member'open at 'both'ends 'and adapted to 'be at least partia-lly irzn-mersed'in an upright position 'in said body of liquid, said member being more d'ense than said liquid .and tending to sink t'hereinA to' a position wherein its lower 'end is closed by engagemen't withthebed of .said body :of liquid, said memberhaving a orossasectional'area 'at the upper end lof the-immersed' portion thereof substantially 'greater 'than'the'cross-sectional' area at 'it's lowerend so that when thenressure inside' said member is 'less thantheflpressure 'outside 'said member; a: buoyant forc'eis: prodnced 'tendingzto liftl'saidmember ofithebed, zanzevacuating: .pipe having fitszinlet'; endin ;communication :with the interior of said tubnlar; member and'spacedxfrom the .lower iend: thereof, and .meansincludngrsaid evaenatingpipeffor ldrawing liquid fromthe interiorfofisaid.tubularmember so as to reduce the pressure therein sutnci'ently vtoliftsaid member from thebed fandthen. draw .sediment-bearng liquid 'intothe lower end .thereofandthence .out through said feivacuatingspipe.

12D. .Apparatu'sifor removing .'.sedimenti from-.a body fof: liquid, lcom'prising .a `container 'for .said body. of liquid. a .'tubuilar :member open .at both ends, -andxadaptedto bev at least parti'ally imm'ersed .infa'n upright position in-said'body of liquid; saidmen'rber being more dense than/'said lliqndffandrtendingfto fsinktherein to 1a. position whereinzits; lowerrfendfis -olosed by engagement With-'the' :bottomfl' of 'said Vxcontainer, ;saidflmember having aforossasectional:areaczat the. upper end of the zimm rsed ;moronz there'of substantia'lls' greater .th-an zthef oross-sectional area .at its.. lower endso that When .the pressurexinslde-said member is :less the ;pressure .outside said member. a linoyant' force. is Aproxzluoed 'tending` to lift said member ofs thecontainer .b0ttom, means to .guide said 'tubular member during Vertical movmeiitv thereof, ain evacuating pipe lhavingI its inl'et end `communication With the'interior'iof said :tnlbular' member and ispaced .from the. lower en'd .thereof, and 'means :includingsaidevacuating pipe forudra'wingflliquid from .the interior of .said t'n'bular member Vso as to .reduce the pressure theremsufi'ciently to liftse'rld` member from the contains-r bottom and draw' sediment-bearing liquid into'the. lower end thereof'-and- .thence out through said evacuat-ing pipe.

Apparatus .for removing .sedimentzfrom va bodyof :liquid aszdefined in olaim .20, in which said t-ulziulary memberis .only partly'immersed; ;said eva'cnating. pipe s'a siphon'havi-ng'- its -inlet' end extending dow'nwardly withinsaid-tubular ;member, and including a fiow limiting valve at the inletof 'said snohon' compris'ing Va asleevexsurronnding said: inleti andA carried by* said? member, and a irod- :xed .onzthe .bottomV of the 'container and having. its .upper end. of substantially'tlie samel'dimensions 'asthe 'si-phon-inlet andzzaligned therewith :and spaced ..theref'rom,' said eleeveh'eing adapted to vcl'oseth'e space betweenithezshahon inletand said :upper fred endvas ;fsaidvmember rea'ches its lowermost position;

1.12; Appa-ratns .for .'removing sedimentfrom *a body'of liq,u-id,.comprisingza tubular memberfopen at ;both ends, 'and adaptedrto :be -at'leastparti'allly immersed in 'annpright potioninssaid. bodynf liquid... said? member' beingmore `denso ".thantsaid li'qmd :and tending :to `sin'k therein 'to ,atposition Wherein 'its' lower end is Vfo'losedzby enga'gement With the bed of said body'of: liqnd,'said'fmember having a'cross-sectional .area at 'the'upper end of the limmersed portion thereofv 'substantia'lly greater 'than' the' cros'si-seotionalf area. at; its.`lower lend vso that the pressureinsideisaid member is :less than the. pressure outside .said member 4a buoyant'force'isfproduced tendinglto lift saidv member od; the: bed, 'an .'evacuating. pipe having its' 'mletv :end communication with. the interior of :said tabular memher'iandspaced -f-no'm the lower end thereof, sai'devacuaxting lp'ipe and sad'tublar 'member fbein'g 'telescopi-ng'ly related so' that said ipipeiservesas a guide for' the 'vertiealv movements ."o'f .said .tubular member, and means inoludingi .'Said 'evacua'ting'pipex for draw' aesaeoe ing liquid from the interior of said tubular member so as to reduce the pressure therein sufficiently to lift said member from the bed and draw sedlment-bearing liquid into the lower end thereof and thence out through said evaeuating pipe.

13. Apparatus for removing sediment from a body of liquid, comprising a tubular member open at both ends, and adapted to be partially immersed in an upright position in said body of liquid, said member being more dense than said liquid and tending to sink therein to a. position wherein its lower end is closed by engagement with the bed of said body of liquid, said member being longer than the depth of said body of liquid, said member having a cross-sectional area at the upper end of the immersed portion thereof substantially greater than the cross-sectional area at its lower end so that when the liquid level inside said member is less than the liquid level outside said member a buoyant force is produced tending to lift said member oif the bed, an evacuating pipe having its inlet end projecting into the interior of said tubular member and spaced below the outside liquid level, and means including said evacuating pipe for drawing liquid from the interior of said tubular member so as to lower the level therein sufiiciently to lift said member from the bed and draw sediment-bearing liquid into the lower end thereof and thence out through said evacuating pipe.

14. A desilting valve for hydraulic installations, comprising a tubular member open at both ends and adapted to be at least partially immersed in an upright position in a body of liquid containing sediment to be removed with the lower end of the member disposed adjacent the bottom of said body liquid, a siphon having its inlet end in communication with the interior of said tubular member and spaoed from the lower end thereof, said siphon being effective to establish a. flow of liquid therethrough when the pressure at its outlet end is lower than the pressure at its inlet end, said flow being effective to lower the pressure within said member, said member having a substantially greater crosssectional area at the upper end of the immersed portion thereof than at its lower end, so that the pressure difference between the inside and outside of the member produces a buoyant force thereon, said buoyant force being effective when it exceeds the net weight of the member to lift the member, said lower pressure inside said member being effective when the member is so lifted to induce an upward flow from adjacent the bottom of the body of liquid carrying sediment therefrom into the member, from which it fiows through the siphon.

15. A desilting valve as defined in claim 14 in which only a portion of the tubular member is immersed, and in which the inlet end of the siphon extends vdownwardly into the open upper end of the tubular member.

16. A desilting valve as defined in claim 14 in which said tubular member is completely immersed, and in which the inlet end of the siphon encircles the open end of the tubular member.

CHARLES BLANCI-IET.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 243,612 Peterson June 28, 1881 367,576 Allen Aug. 2, 1887 534,203 v Daly Feb. 12, 1895 833,150 Attenhofer Oct. 16, 1906 982,734 Martinelli Jan. 24, 1911 1,059,060 p McLaughlin Apr. 15, 1913 1,107,391 Welch Aug. 18, 1914 1,350,204 Allen Aug. 17, 1920 1,908,691 Coe May 16, 1933 2,140,059 Simonsen Dec. 13, 1938 2,199,673 Ronning May 7, 1940 2,342,024 Walker Feb. 15, 1944 FOREIGN PATENTS Number Country Date 583,941 France Nov. 10, 1924 512,732 Great Britain Sept. 25, 1939 

